AFGHANISTAN — As the American patrol made its way to the provincial governor’s compound in Asadabad, Afghanistan, a lone figure approached the group, a square bulge visible under his shirt.

Sgt. Andrew J. Mahoney and Capt. Florent Groberg rushed the man, tackling him to the ground as he detonated his suicide vest.

For his actions that day, Mahoney was awarded the Silver Star, the nation’s third-highest award for valor, during a ceremony April 22 at Fort Carson, Colo.

A valor award for Groberg is pending approval, in the wake of a deadly twin suicide-bomber attack that killed four, including the senior enlisted soldier for 4th Brigade Combat Team, 4th Infantry Division.

“I was doing my job,” he said. “I don’t think I did anything above and beyond.”

Mahoney, who recently re-enlisted for three more years of service and is still assigned to 4th BCT, suffered a severe soft-tissue wound to his left forearm and shrapnel wounds to his right shoulder and right leg.

He’s “90 percent healed up now,” he said, but he still suffers from nerve and tendon damage in his left arm.

“It may come back in the future, it may not,” the 28-year-old said doctors told him. “I’m right-handed, luckily.”

It was late morning Aug. 8, 2012, when Mahoney and the security detachment flew with the brigade commander at the time, Col. James Mingus, and his command team from Jalalabad to Asadabad in eastern Afghanistan. The soldiers flew in on two UH-60 Black Hawk helicopters, landing at Forward Operating Base Faiz. From there, the group of about 30 Americans and Afghans set out for the short walk to the provincial governor’s compound, Mahoney said.

As they traveled north, they came to a bridge that spanned a canal, according to the narrative accompanying Mahoney’s award. When they reached this “natural choke point,” according to the narrative, Mahoney saw the lone figure approaching the group.

Mahoney immediately saw the bulge under the man’s clothing and assumed it was a suicide vest, according to the narrative.

Instinctively, Mahoney and Groberg, the personal security detachment commander, “both took the guy to the ground and make sure he didn’t break the perimeter of our main group,” Mahoney said.

“There was no time for anything to go through our heads. It was just reacting,” he said. “There wasn’t any time to think about anything.”

As the soldiers pushed the man to the ground, he detonated his vest, Mahoney said.

After the explosion, Mahoney quickly assessed his surroundings and ran to make sure Mingus was OK.

Mahoney, Mingus and a lieutenant colonel sought cover behind a nearby wall in case there was a secondary explosion or follow-on attack, he said.

It wasn’t until Mahoney was being checked by a medic that he learned there were two suicide bombers that day, he said.

The second bomber was across the street from the group, approaching from a different direction, Mahoney said.

“When his partner detonated, he lost his courage and went for it instead of trying to get closer,” he said.

The second bomber’s vest, which like the first bomber’s vest was packed with ball bearings, exploded almost simultaneously with the first vest, and it did most of the damage, Mahoney said.

Command Sgt. Maj. Kevin J. Griffin, 45, the brigade’s senior enlisted soldier, was killed in the attack. Also killed were Maj. Thomas E. Kennedy, 35, the brigade’s fire support coordinator; Air Force Maj. Walter D. Gray, 38, of the 13th Air Support Operations Squadron at Fort Carson; and Ragaei Abdelfattah, who was on his second voluntary tour with the U.S. Agency for International Development.

Mingus was unharmed.

Groberg suffered significant wounds to his left leg, Mahoney said, and is still assigned to the warrior transition unit at Walter Reed National Military Medical Center.